. Author manuscript; available in PMC: 2011 Mar 9.

Published in final edited form as: Biochemistry. 2010 Mar 9;49(9):1931–1942. doi: 10.1021/bi9021268

Table 5.

Steady state kinetic constants for hydrolysis of acetate esters and ε-caprolactone by wild-type PFE and L29P PFE.^a

Enzyme	substrate	k_cat [s^-1]	K_m [mM]	k_cat/K_m [s^-1 M^-1]
Wild-type PFE	methyl acetate	25 ± 1	43 ± 3	600
Wild-type PFE	ethyl acetate	9 ± 1	33 ± 1	300
Wild-type PFE	ε-caprolactone	>140	>2000	50^b
L29P PFE	methyl acetate	7.7 ± 0.2	50 ± 5	200
L29P PFE	ethyl acetate	0.67 ± 0.05	160 ± 30	4
L29P PFE	ε-caprolactone	11 ± 1	39 ± 1	280

Rates of hydrolysis were measured at 23 °C using the pH indicator p-nitrophenol at pH 7.2 in 5.0 mM BES buffer.

Determined from the initial slope of rate versus substrate concentration, R² = 0.996.